MILKING SYSTEM WITH VARIABLE PRESSURE SOURCE

Description

BACKGROUND

[0001] The invention relates to a method and apparatus for milking mammals, including cows.

[0002] Milking systems withdraw milk from the milk secreting glands of mammals by applying negative pressure (pressure below atmospheric pressure), i.e. vacuum, to the teat. A plurality of teat cups are provided, each having a liner, or inflation, around a respective teat, and defining a milk flow passage within the liner below the teat, and a pulsation chamber outside the liner between the liner and the teat cup. The milk flow passage within the liner supplies milk to a milking claw which also receives milk from the milk flow passages of the other liners of the other teat cups.

[0003] Simply supplying a constant vacuum to the teat is not desirable because it causes the tissue of the teat to become engorged with blood and lymph. When these fluids are confined to their normal spaces within the teat, the condition is called congestion. When the fluids leave their normal spaces, it is called oedema. These conditions may result in pain or discomfort to the mammal being milked, and swelling of the tissue which may constrict the duct through which milk is being withdrawn, thereby slowing the flow of milk. The slowing of milk flow due to the effects of congestion may be accompanied by a reduced volume of milk available for removal because the discomfort may interfere with the milk ejection reflex by which the mammal presents her milk to the teat.

[0004] Various attempts have been made to ameliorate the undesirable effects of vacuum on the teat by carefully shaping the teat cup and liner to support the teat as well as possible, and by periodically relieving the vacuum to the teat. The liner periodically collapses around and below the teat, providing massage to the teat. The massage compresses the end of the teat, thereby actively forcing fluids out of the teat apex. The massaging action of the liner also provides stimulation to the teat whereby the milk ejection reflex is strengthened. In some cases, the milk ejection reflex may be elicited solely by the action of the pulsating liner. The pulsation cycle has an on portion and an off portion. Milk is withdrawn from the teat through the liner to the claw during the on portion. During the off portion, the closed liner stops milk flow from the teat.

[0005] In the prior art, a two-way valve, or pulsator, alternates between a first condition connecting a negative pressure source, i.e. vacuum, to the pulsation chamber, and a second condition supplying atmospheric or higher pressure to the pulsation chamber. The two-way valve provides a pulsation cycle having an on portion during the first condition of the valve, and an off portion during the second condition of the valve. The valve or pulsator simply transfers the pulsation chamber connection between two alternative sources, namely vacuum and atmosphere.

[0006] In the prior art, it is known to replace the atmospheric pressure source with a source above atmospheric pressure for some part of the milking (positive pressure pulsation). It is also known to use a vacuum level other than milking vacuum to replace the vacuum source. It is also known to vary the repetition rate or ratio between atmospheric and vacuum phases of pulsation. These changes may be varied during milking, either on a fixed program or under the control of the flow of milk from the mammal. The rate of transition from atmospheric to vacuum may be changed by selecting the sizes of orifices used in the pulsator. However, the pulsator remains a two-way valve.

[0007] In DE-A-36 09 275 milk flow variations are measured, during milking and the results interpreted by computer, to deliver values which aid the selection of milking parameters.

[0008] In one aspect of the invention there is provided a method for milking a mammal, comprising the features of claim 1.

[0009] In another aspect of the invention there is provided milking apparatus for milking a mammal, comprising the features of claim 20.

[0010] In the present invention, the pulsator is replaced with a variable pressure source, and a controllably variable pressure is supplied to the pulsation chamber. The pressure is varied along a controllably variable pressure curve of selectable waveshape.

[0011] The pulsation cycle is shortened by shortening the transition time between first and second pressure levels providing on and off portions of the pulsation cycle. The shape and slope of the transition pressure waveform between the noted first and second levels is controlled along a selected pattern. During the transition, the pressure is varied at sequenced rates which reduces delay in liner movement and which generate a change in internal liner volume at a maximum desired rate. This is accomplished by varying the rate of pressure change. During the transition, the pressure is maintained at one of the noted pressure levels until the liner is ready to move, and then the pressure is abruptly changed to an intermediate level to begin liner movement, and then the pressure is changed at a slower rate to complete liner movement, and then the pressure is abruptly changed to the other of the noted pressure levels, all during the transition between the on and off portions of the pulsation cycle. During the transition, pressure is initially applied to the pulsation chamber at a first rate of change, and then applied at a second rate of change which is less than the first rate of change, and then applied at a third rate of change which is greater than the second rate of change, such that during the transition, the pulsation chamber is sequenced through changing pressure rates, including from the first rate to the second rate, and from the second rate to the third rate, all during the transition between the on and off portions of the pulsation cycle.

[0012] In one embodiment, the invention enables the noted transition time to be reduced from 0.2 second to 0.05 second, and the pulsation cycle to be reduced from 0.9 second to 0.6 second, while still withdrawing the same amount of milk, i.e. the same amount of milk is withdrawn in one-third less time, or stated another way, fifty percent more milk is withdrawn in the same amount of time.

[0013] In another aspect of the invention, a milking interval is provided having a plurality of pulsation cycles, and the pressure change transition time from an upper pressure level to a lower pressure level during pulsation cycles at the end of the milking interval is lengthened to provide a decreasing-pressure transition time during pulsation cycles at the end of the milking interval which is longer than the decreasing-pressure transition time during pulsation cycles in the middle of the milking interval, to provide a slower rate of liner opening movement during pulsation cycles at the end of the milking interval than the rate of liner opening movement during pulsation cycles in the middle of the milking interval, to open the liner more slowly at the end of the milking interval than during the middle of the milking interval, to limit loss of adhesion between a less than full teat and the interior of the liner at the end of the milking interval. In a further aspect, the pressure change transition time from the upper pressure level to the lower pressure level during pulsation cycles at the beginning of the milking interval is shortened to provide a decreasing-pressure transition time during pulsation cycles at the beginning of the milking interval which is shorter than the decreasing-pressure transition time during pulsation cycles in the middle of the milking interval, to provide a faster rate of liner opening movement during pulsation cycles at the beginning of the milking interval than the rate of liner opening movement during pulsation cycles in the middle of the milking interval, to open the liner more rapidly at the beginning of the milking interval than during the middle of the milking interval, to provide deeper teat penetration into the liner and faster milking. The pressure change transition time from the upper pressure level to the lower pressure level is varied to provide a first decreasing-pressure transition time from the upper pressure level to the lower pressure level during pulsation cycles at the beginning of the milking interval, a second decreasing-pressure transition time from the upper pressure level to the lower pressure level during pulsation cycles in the middle of the milking interval, and a third decreasing-pressure transition time from the upper pressure level to the lower pressure level during pulsation cycles at the end of the milking interval, wherein the first transition time is shorter than the second transition time, and the third transition time is longer than the second transition time. The pressure applied to the pulsation chamber during on portions of the pulsation cycles is varied during the milking interval to open the liner at a first rate of liner opening movement during pulsation cycles at the beginning of the milking interval, a second rate of liner opening movement during pulsation cycles in the middle of the milking interval, and a third rate of liner opening movement during pulsation cycles at the end of the milking interval, wherein the first rate is faster than the second rate, and the third rate is slower than the second rate.

[0014] In another aspect of the invention, a milking interval is provided having a plurality of pulsation cycles, and the pressure applied to the pulsation chamber by the variable pressure source is varied during on portions of pulsation cycles at the end of the milking interval to open the liner less at the end of the milking interval than during the middle of the milking interval, to limit loss of adhesion between a less than full teat and the interior of the liner at the end of the milking interval. In a further aspect, the pressure is varied during on portions of pulsation cycles at the beginning of the milking interval to open the liner more at the beginning of the milking interval than during the middle of the milking interval, to provide deeper teat penetration into the liner and faster milking. The pressure is varied to open the liner to a first diameter at the beginning of the milking interval, and to a second diameter during the middle of the milking interval, and to a third diameter at the end of the milking interval, the first diameter being greater than the second diameter, and the second diameter being greater than the third diameter.

[0015] In another aspect of the invention, the pressure applied to the pulsation chamber during the off portion of the pulsation cycle is controllingly varied to vibrate and massage the teat during the off portion by alternately increasing and decreasing the pressure applied to the pulsation chamber during the off portion at a higher frequency than the repetition frequency of the pulsation cycle.

[0016] In another aspect of the invention, the pressure applied to the pulsation chamber during the on portion of the pulsation cycle is controllingly varied to alternately increase and decrease the pressure at a higher frequency than the repetition frequency of the pulsation cycle, to bump and vibrate the teat and further stimulate the milk ejection reflex of the mammal.

[0017] In another aspect of the invention, the length of the on portion of the pulsation cycle is changed during the milking interval to accommodate the nonsteady rate of milk flow inherently resulting from the anatomical structure of the teat, and the reduced supply from the milk secreting glands which occur as milking progresses.

BRIEF DESCRIPTION OF THE DRAWINGS

Prior Art

[0018] 

FIG. 1 schematically illustrates a milking system known in the prior art.

FIG. 2 shows a teat cup and liner during the on portion of a pulsation cycle as known in the prior art.

FIG. 3 is like FIG. 2 and illustrates the off portion of a pulsation cycle.

FIG. 4 is a graph showing pressure in the pulsation chamber during a pulsation cyde as known in the prior art.

FIG. 5 shows liner movement during the pulsation cycle of FIG. 4.

Present Invention

[0019] 

FIG. 6 shows a milking system in accordance with the present invention.

FIG. 7 is a graph showing pressure in the pulsation chamber during a pulsation cycle in accordance with the invention.

FIG. 8 shows liner movement during the pulsation cycle of FIG. 7.

FIG. 9 shows a milking interval having a plurality of pulsation cycles.

FIG. 10 shows a milking interval having a plurality of pulsation cycles, and shows a further embodiment.

FIG. 11 shows differing liner diameters during the milking interval of FIG. 10.

FIG. 12 is like FIG. 7 and shows a further embodiment.

DETAILED DESCRIPTION

Prior Art

[0020] FIG. 1 shows a milking system 10 having a plurality of teat cups such as 12, 14 connected to respective teats such as 16, 18 depending from the udder 20 of a mammal 22 such as a cow. Each teat cup has a liner or inflation such as 24, 26 around a respective teat, and defining a milk flow passage such as 28, 30 within the liner below the teat, and a pulsation chamber such as 32, 34 outside the liner between the liner and the teat cup. The teat cup and liner are shown and described in U.S. Patent 4,530,307, incorporated herein by reference. A milking claw 36, for example as shown in U.S. Patent 4,537,152, incorporated herein by reference, has a plurality of inlets receiving milk through tubes such as 38, 40 connected to respective teat cups to receive milk from respective milk flow passages such as 28, 30. The daw has a discharge tube 42 connected to milk collection container 44 having a vacuum connection tube 46 connected to a source of negative pressure 48. There are a multitude of arrangements of this negative pressure source, as well known in the art. Negative pressure source 48 applies substantially constant negative pressure (vacuum), relative to atmospheric pressure, through claw 36 to milk flow passages 28, 30.

[0021] The system has a pulsation cycle with an on portion and an off portion. Milk flows from the teat towards claw 36 during the on portion. A two-way valve or pulsator 50 is connected to each of the teat cups at a connection tube such as 52 and has first and second conditions alternately and cyclicly connecting the teat cup to the negative pressure source 48 through connection tube 54 during the on portion of the pulsation cycle, and connecting the teat cup to atmosphere through connection tube 56 during the off portion of the pulsation cycle. There are a multitude of arrangements for making the connections to the pulsator, as well known in the art. It is also known in the prior art to connect the teat cup to a source of positive pressure, relative to atmospheric pressure, during the off portion of the pulsation cycle, e.g. by supplying connection tube 56 with a source of positive pressure. During the off portion of the pulsation cycle, the positive pressure or atmospheric pressure applied through connection tube 56, valve 50, and connection tube 52 to pulsation chamber 32 of teat cup 12 collapses and closes liner 24 below teat 16, FIG. 3, to block milk flow, and to relieve the teat from the negative pressure applied from source 48 through connection tube 46, container 44, connection tube 42, claw 36, and connection tube 38 to milk flow passage 28 at the lower end of liner 24. During the on portion of the pulsation cycle, negative pressure from source 48 is applied through connection tube 54, valve 50, and connection tube 52 to pulsation chamber 32 of teat cup 12, such that liner 24 opens to its normally open position, FIG. 2, and milk is withdrawn from teat 16.

[0022] In FIG. 4, the pressure in pulsation chamber 32 is shown at solid line 58. In FIG. 5, the movement of liner 24 is shown at solid line 60. The period of the pulsation cycle is about 0.9 second.

[0023] During the off portion of the pulsation cycle, the pressure in pulsation chamber 32 is at atmospheric pressure, i.e. zero relative to atmosphere, as shown at 62, FIG. 4, and again at 64, and liner 24 is in its closed position of FIG. 3 which is illustrated at 66 in FIG. 5, and again at 68. Pulsator valve 50 is switched to its alternate condition to initiate the transition from the off portion to the on portion of the pulsation cycle. Switching of valve 50 to its alternate condition connects negative pressure source 48 through connection tube 54, valve 50, and connection tube 52 to pulsation chamber 32, such that the pressure in pulsation chamber 32 falls as shown at 70, FIG. 4, to lower level 72 which is a negative pressure, relative to atmosphere, as illustrated at -15 inches Hg, mercury, which is the negative pressure supplied by source 48. During this transition, the liner moves as shown at 74, FIG. 5, to its open condition of FIG. 2 which is illustrated at 76 in FIG. 5. The duration of pressure transition 70, FIG. 4, varies greatly from one system to the next, but in this example is 0.2 second.

[0024] During the on portion of the pulsation cycle, the pressure in pulsation chamber 32 is at level 72, and the position of liner 24 is fully open as shown in FIG. 2, which is illustrated at 76 in FIG. 5. The duration of the on portion of the pulsation cycle varies greatly from one system to the next, but in this example is 0.4 second. At the end of the on portion, pulsator valve 50 is switched back to its other position, to connect atmospheric connection tube 56 through valve 50 and connection tube 52 to pulsation chamber 32, such that the pressure in pulsation chamber 32 rises as shown at 78, FIG. 4, to level 64, and the cycle is repeated. During transition 78, the liner moves as shown at 80, FIG. 5, to its closed position at 68. The duration of pressure change transition 78 varies greatly from one system to the next, but in this example is 0.2 second. The duration of the off portion of the pulsation cycle at 64 varies greatly from one system to the next, but in this example is 0.1 second. A milking interval lasts about four to five minutes and is composed of a plurality of pulsation cycles, for instance about 250 to 350 cycles in the example given.

Present Invention

[0025] FIGS. 6-12 illustrate the present invention and use like reference numerals from FIGS. 1-5 where appropriate to facilitate understanding. The two-way valve or pulsator 50 of FIG. 1 is replaced by a variable pressure source 82 in FIG. 6, and controllably variable pressure is supplied to pulsation chamber 32. The variable pressure source is preferably a transducer, such as provided by a Bellofram Type 1000 Transducer Model 961-116-000, available from Bellofram Corporation, State Route 2, P.O. Box 305, Newell, West Virginia 26050. The transducer as connected between positive and negative pressure sources 84 and 48 at respective connection tubes 86 and 54, and supplies output pressure at connection tube 52 to pulsation chamber 32 of teat cup 12. The positive pressure port of the transducer is connected by connection tube 86 to positive pressure source 84. The vent port of the transducer is not connected to atmosphere, but instead is connected by connection tube 54 to negative pressure source 48 as a reference. The transducer controls the output pressure along a controllably variable pressure curve of selectable waveshape as set by controller or timer 88 providing a time dependent pattern, though other alternatives are possible, to be described.

[0026] A pulsation cycle is provided by applying a first pressure level 90, FIG. 7, from the variable pressure source to pulsation chamber 32 to open liner 24, FIG. 2, below teat 16 to provide an on portion of the pulsation cycle, and applying a second pressure level 92, higher than level 90, from the variable pressure source to pulsation chamber 32 to collapse and close liner 24, FIG. 3, below teat 16 to provide an off portion of the pulsation cycle. The pressure supplied to pulsation chamber 32 is controllingly varied during the transition 94 from the off portion 96 to the on portion 90 of the pulsation cycle, and during the transition 98 from the on portion 90 to the off portion 92 of the pulsation cycle. During these transitions, the rate of change of pressure supplied by the variable pressure source to pulsation chamber 32 is varied.

[0027] As shown during transition 94, FIG. 7, the pressure is abruptly changed at 100 at the beginning of the transition, and then varied at a slower rate of change at 102, and then abruptly changed at 104 at the end of the transition, such that there is a first abrupt pressure change 100 followed by a slower rate of pressure change 102 followed by a second abrupt pressure change 104, all during transition 94. Likewise during transition 98, there is a first abrupt pressure change 106 followed by a slower rate of pressure change 108 followed by a second abrupt pressure change 110, all during transition 98. During off portion 96 of the pulsation cycle, liner 24 is in its closed position of FIG. 3, as illustrated at 112 in FIG. 8. During transition 94, FIG. 7, the liner moves as shown at 114, FIG. 8, to its open position 116 during on portion 90 of the pulsation cycle. During transition 98, the liner moves as shown at 118 back to its closed position as shown at 120. Pressure levels 50 and 92 are alternately and repetitively applied to pulsation chamber 32 to provide a plurality of repetitive pulsation cycles, FIGS. 9 and 10, each cycle having an on portion during application of pressure level 90, and an off portion during application of pressure level 92. It is recognized that the instantaneous pressure changes 100, 104, 106, and 110 in FIG. 7 are idealized, and in fact some small amount of time elapses during these changes.

[0028] The pulsation cycle is shortened by shortening the transition time between pressure levels 90 and 92. In FIG. 7, the transition time of each of transitions 94 and 98 is 0.05 second, as compared to 0.2 second of FIG. 4. The shortened transition time in turn provides a shortened pulsation cycle time of 0.6 second in FIG. 7, as compared to 0.9 second in FIG. 4. The length of the on portion of the pulsation cycle is 0.4 second in each of FIGS. 7 and 4. The length of the off portion of the pulsation cycle is 0.1 second in each of FIGS. 7 and 4.

[0029] The transition time between pressure levels 90 and 92 is shortened by varying the rate of change of pressure applied to pulsation chamber 32 during the transition between on and off portions of the pulsation cycle. At least two different rates of change of pressure are provided during the transition, and pressure is applied to the pulsation chamber at each of such rates of change during the transition. It is preferred that the pressure be sequenced through changing pressure rates during the transition, including from a first rate such as 100 to a second rate such as 102, and from the second rate 102 to a third rate such as 104, all during transition 94. It is preferred that the first and third rates 100 and 104 be substantially instantaneous, and that the second rate 102 be substantially linear.

[0030] During the transition 94 from the off portion of the pulsation cycle at 96 to the on portion of the pulsation cycle at 90, the pressure applied to pulsation chamber 32 is abruptly decreased at 100, and then is decreased at 102 at a rate providing substantially constant rate of volume change within liner 24 as it opens at 114, and then the pressure is abruptly decreased at 104 to level 90. During the transition 98 from the on portion of the pulsation cycle at 90 to the off portion of the pulsation cycle at 92, the pressure is abruptly increased at 106, and then the pressure is increased at 108 at a rate providing a substantially constant rate of volume change within liner 24 as it closes at 118, and then the pressure is abruptly increased at 110 to upper level 92.

[0031] The noted sequencing during transition 94 generates a linear change in internal liner volume at a maximum desired rate and reduces delays in liner movement by maintaining the pressure at upper level 96, FIG. 7, until it is desired to cause liner 24 to move, then abruptly changing the pressure to an intermediate level at 122 at which liner movement will begin as shown at 114, FIG. 8, then changing the pressure at a slower rate at 102 to an intermediate level at 124 to complete liner movement, and then abruptly changing the pressure at 104 to lower level 90. Likewise during transition 98, the sequencing generates a linear change in internal liner volume at a maximum desired rate and reduces delays in liner movement by maintaining the pressure at lower level 90 until it is desired to cause liner 24 to move, then abruptly changing the pressure to an intermediate level at 126 at which liner movement will begin, then changing the pressure at a slower rate at 108 to an intermediate level at 128 to complete liner movement at 118, and then abruptly changing the pressure at 110 to higher level 92. The sequencing and pressure change rates are preferably chosen such that the transition time between on and off portions of the pulsation cycle is limited only, or at least primarily, by the desired rate of movement of the liner between open and closed conditions, typically about 0.05 second, to in turn generate the maximum desired rate of movement of the liner. The transition points, 122, 124, 126, 128, FIG. 7, correspond to those pressure levels at which liner movement actually begins or ends. The efficiency of the waveform at FIG. 7 over that of FIG. 4 comes from the reduction in time wasted in the prior art waiting for the pressure to move from level 96 to 122, 124 to 90, 90 to 126, and 128 to 92, all of which used substantial time in the prior art.

[0032] A milking interval 130, FIG. 9, is composed of a plurality of pulsation cycles 132. As noted above, the length of each pulsation cycle is about 0.6 second. The length of milking interval 130 is typically about four to five minutes, though may be shorter or longer depending on when milk flow rate decreases below a given level, and the amount of milk to be removed.

[0033] The milking interval 130, FIG. 9. may simply consist of repetition of cycles such as 132, or the individual cycles may be varied as milking progresses. One example of this, also shown in FIG. 9, utilizes the fact, previously known in the art, that rapid opening of the liner tends to decrease friction between liner and teat. This is desirable at the start of milking because it enhances penetration of the teat into the liner. Near the end point of milking, however, pressure of milk inside the teat is reduced, reducing friction between teat and liner, and in this condition, opening the liner more slowly is beneficial. The present invention allows utilization of this knowledge by opening the liner rapidly at the beginning of milking, but slowly at the end of milking. Milking interval 130 has a first or initial sub-interval 134, for example lasting for about the first fifteen seconds, a second or main sub-interval 136, for example lasting about three to four minutes, and a third or final sub-interval 138, for example lasting about a minute. In the cycles during initial sub-interval 134, the decreasing-pressure transition time is shown at 140. The pressure decreases at 142 from upper pressure level 144 to lower pressure level 146. In the cydes during main sub-interval 136, the decreasing-pressure transition time is shown at 148. The pressure decreases at 150 from the upper pressure level 144 to the lower pressure level 146. Transition time 148 is the same as the transition time for transition 94 in FIG. 7. In the cycles during the final sub-interval 138, the decreasing-pressure transition time is shown at 152. The pressure decreases at 154 from the upper pressure level 144 to the lower pressure level 146. Transition time 140 is less than transition time 148. Transition time 152 is greater than transition time 148.

[0034] The pressure change transition time 152, FIG. 9, from the upper pressure level to the lower pressure level during pulsation cycles at the end of the milking interval is lengthened to provide a decreasing-pressure transition time 152 during pulsation cycles at the end of the milking interval which is longer than the decreasing-pressure transition time 148 during pulsation cycles in the middle of the milking interval, to provide a slower rate of liner opening movement during pulsation cycles at the end of the milking interval than the rate of liner opening movement during pulsation cycles in the middle of the milking interval, to open the liner more slowly at the end of the milking interval than during the middle of the milking interval, to limit loss of adhesion between a less than full teat and the interior of the liner at the end of the milking interval. Pressure change transition time 140 from the upper pressure level to the lower pressure level during pulsation cydes at the beginning of the milking interval is shortened to provide a decreasing-pressure transition time 140 during pulsation cycles at the beginning of the milking interval which is shorter than the decreasing-pressure transition time 148 during pulsation cydes in the middle of the milking interval, to provide a faster rate of liner opening movement during pulsation cycles at the beginning of the milking interval than the rate of liner opening movement during pulsation cycles in the middle of the milking interval, to open the liner more rapidly at the beginning of the milking interval than during the middle of the milking interval, to provide deeper teat penetration into the liner and faster milking. The pressure applied to the pulsation chamber is varied during the decreasing pressure portions of the pulsation cycles to open the liner at a first rate of liner opening movement corresponding to pressure change rate 142 during pulsation cycles at the beginning of the milking interval, a second rate of liner opening movement corresponding to pressure change rate 150 during pulsation cycles in the middle of the milking interval, and a third rate of liner opening movement corresponding to pressure change rate 154 during pulsation cycles at the end of the milking interval. Rate 142 is faster than rate 150. Rate 154 is slower than rate 150.

[0035] In a further embodiment, FIG. 10, a milking interval 156 is composed of a plurality of pulsation cycles 158. As noted above, the length of each pulsation cycle 158 is about 0.6 second. The length of milking interval 156 is typically about four to five minutes, through may be shorter or longer depending on when milking flow rate decreases below a given level. During on portions such as 160 of pulsation cycles at the end of milking interval 156, the pressure applied to pulsation chamber 32 is varied to provide a higher pressure level 162 than the pressure level such as 164 during on portions of pulsation cycles such as 166 during the middle of milking interval 156, such that liner 24 opens less at the end of milking interval 156 than during the middle of milking interval 156, to limit loss of adhesion between a less than full teat and the interior of liner 24 at the end of milking interval 156. During on portions such as 168 of pulsation cycles at the beginning of milking interval 156, the pressure applied to pulsation chamber 32 is varied to a lower pressure level 170 than pressure level 164 during on portion 166 of pulsation cycles during the middle of milking interval 156, to open liner 24 more at the beginning of milking interval 156 than during the middle of milking interval 156, to provide deeper teat penetration into liner 24 and faster milking. Pressure level 170 opens liner 24 to diameter 172, FIG. 11, at the beginning of milking interval 156. Pressure level 164 opens liner 24 to diameter 174 during the middle of milking interval 156. Pressure level 162 opens liner 24 to diameter 176 at the end of milking interval 156. Diameter 172 is greater than diameter 174. Diameter 174 is greater than diameter 176.

[0036] In a further embodiment, the pressure applied to pulsation chamber 32 is varied during the off portion 178, FIG. 12, of the pulsation cycle, including increasing the pressure, as at 180, 182, applied to the pulsation chamber during the off portion of the pulsation cycle to increase the massage force of liner 24 on teat 16. The teat is vibrated and massaged during off portion 178 of the pulsation cycle by alternately increasing and decreasing the pressure applied to pulsation chamber 32 during off portion 178 at a higher frequency than the repetition frequency of the pulsation cycle. The pressure applied to pulsation chamber 32 is also varied during the on portion 184, FIG. 12, of the pulsation cycle by alternately increasing and decreasing the pressure at a higher frequency than the repetition frequency of the pulsation cycle to bump and vibrate teat 16 and further stimulate the milk ejection reflex of the mammal.

[0037] It is further recognized that the transducer, 82 in FIG. 6, is actually a non-ideal device and therefore its output may not exactly follow the input electrical signal. The present invention permits partially correcting for this non-ideal characteristic by incorporating a feedback signal from the transducer output to modify its input, or more simply by overdriving the transducer to increase the rate of change of output pressure that can be achieved.

[0038] It is further recognized that the thin liner disclosed in commonly owned co-pending U.S. application Serial No. 07/714,491, filed June 13, 1991, is ideally suited to control by the pulsation system of this invention. The thin liner transmits pulsation chamber pressure to the teat with little distortion caused by the stiffness of the liner wall. Therefore the electrical signal to the transducer may be a direct representation of the pressure waveform desired to be imposed upon the teat.

[0039] Controller 88 is preferably provided by a Compaq computer programmed by the "Asystant +" program by MacMillan Software Company and interfaced to the Bellofram Type 1000 transducer through an AD694 current transmitter available from Analog Devices, One Technology Way, P.O. Box 9106, Norwood, Maine 02062-9106. Alternatively or in addition to timed waveform control of the pressure transducer, the pressure may be varied according to milk flow rate as monitored by sensor 186, which may be provided as disclosed in "Monitoring The Flow Of Milk Within Machine Milked Teat By Observing Doppler Shift Of Back-Scattered Ultrasound", P. Thompson and L. Campbell, Transactions of the ASAE, American Society of Agricultural Engineers, Vol. 17, No. 3, pp. 496, 497, 498, 499, and 504, 1974. For example, in addition to acting as a timer, controller 88 also responds to reduced milk flow rate as indicated by sensor 186, and shortens the duration of the on portion of the pulsation cycle, by terminating the on portion and initiating the off portion of the pulsation cycle. For example, the duration of an on portion 188, FIG. 10, of a pulsation cycle occurring later in a milking interval may be shorter than the duration of an on portion 166 of a pulsation cycle occurring earlier in the milking interval. This further reduces milking time and the length of the milking interval by eliminating nonefficient segments of on portions of the pulsation cycles, and keeping the liner open only as long as there is sufficient milk flow to justify same. When milk flow rate drops below a given level, the liner is closed and a new pulsation cyde is initiated.

[0040] Because of the anatomical structure of the teat, milk will not flow at a steady rate during the time that the liner is open. Rather, milk will flow at a relatively constant rate beginning when the liner first opens, but this rate will decline. The reason for the decline is the swelling of the tissue surrounding the teat canal as a reaction to the application of milking vacuum, i.e. the negative pressure in milk flow passage 28. The collapse of the liner around the teat during the off portion of the pulsation cycle removes physiological fluids from the teat end, reducing its swelling, and enabling the resumption of higher rate milk flow when the on portion of the next pulsation cyde begins. With a conventional two-way valve or pulsator 50, the transitions between off and on portions of the pulsation cycle begin at a high rate of pressure change, but the rate of pressure change decreases as the pressure approaches the next level. This reduction is because the rate of air flow through the ports of the conventional pulsator is dependent upon the pressure difference across the open port. The timebase scaling factor of these transitions is adjusted by selecting an appropriate port size, with the goal being to achieve a rapid transition without exceeding the limit imposed by the ability of milk tube 38 to accommodate the air flow which moves into or out of the liner as it opens or closes. The result of this constraint is that the transition of pulsation pressure from level 62, FIG. 4, to level 72, takes 0.2 second, even though the liner actually moves from its closed position 66, FIG. 5, to its open position 76 in less time. In contrast, by providing a variable pressure source and supplying controllably variable pressure to the pulsation chamber, including during the noted transitions, the shape of the transition pressure waveform can be entirely different. In the liner opening phase, the pressure falls until the liner is just ready to begin opening. This stage of falling pressure can be very abrupt, because it is not accompanied by movement of the liner. Next, pressure continues to fall along a curve such as 102, FIG. 7, which gives constant rate of volume change within the liner as it shifts from the closed to the open position. Finally, the pressure can again abruptly shift to milking vacuum, i.e. negative pressure level 90, FIG. 7. These stages are reversed as the liner closes again in response to the transition from the on to the off portion of the pulsation cycle. A fixed port pulsator such as 50 does not permit the transition slope to be modified or otherwise shaped as desired. On-off cycle times, and upper and lower limits of pulsation, can be varied with a two-way valve, but transitional slopes cannot be changed or shaped or otherwise controlled unless the fixed port size is changed.

[0041] The timing pattern provided by controller 88 and/or the flow rate provided by sensor 186 may vary the repetition rate of the pressure curve waveshape, to provide a plurality of pulsation cycles of variable duration during the milking interval, or may vary the pressure levels. As a further alternative to a pressure transducer, the variable pressure source can be provided by various combinations of two-position valves connected to synthesize a desirable waveshape, particularly the slope providing the desired rates of change during the noted transitions. As a further alternative, the variable pressure source is provided by a pressure source and a valve with a variable orifice.

[0042] It is recognized that various equivalents, alternatives and modifications are possible within the scope of the appended claims.

Claims

1. A method for milking a mammal, comprising:

providing a teat cup (12; 14) having a liner (24; 26) for location around a teat of a mammal;

defining a milk flow passage (28; 30) within said liner (24; 26) and a pulsation chamber (32; 34) between said liner (24; 26) and said teat cup (12; 14);

applying a negative pressure below atmospheric pressure to said milk flow passage (28; 30);

supplying a negative pressure to said pulsation chamber (32; 34) during an on portion of said pulsation cycle;

supplying a higher pressure to said pulsation chamber during an off portion of said pulsation cycle;

characterized by the use of a variable pressure source (82) for controllably varying the rate of pressure change in said pulsation chamber (32; 34)
without using a two-way valve pulsator alternating between a first condition connecting a negative pressure source to the pulsation chamber and a second condition supplying atmospheric or higher pressure as on and off portions of a pulsation cycle;
the method comprising supplying a controllably variable pressure to said pulsation chamber (32; 24) and varying the pressure supplied to said pulsation chamber (32; 34) along a controllably variable pressure curve of selectable waveshape,
the method further comprising abruptly changing the pressure at the beginning of the transition from at least one of said on and off portions of said pulsation cycle to the other of said on and off portions of said pulsation cycle, and then varying the pressure at a slower rate of change, all during said transition.

2. A method as claimed in any preceding claim, wherein a negative pressure source (48) commonly supplies said negative pressure applied to said milk flow passage (28,30) and said negative pressure applied to said pulsation chamber (32,34).

3. A method as claimed in any preceding claim comprising controllably varying the pressure applied to said pulsation chamber during said on portion of said pulsation cycle.

4. A method as claimed in any preceding claim comprising abruptly changing the pressure at the end of said transition following said slower rate of pressure change, so as to provide a first abrupt pressure change followed by a slower rate of pressure change followed by a second abrupt pressure change, all during said transition.

5. A method as claimed in any preceding claim comprising abruptly changing the pressure applied to said pulsation chamber at a rate sufficiently fast that the transition time between said on and off portions of said pulsation cycle is limited only by the desired rate of movement of said liner between open and closed conditions.

6. A method as claimed in claim 5 comprising changing the pressure applied to said pulsation chamber at a rate generating the maximum desired rate of movement of said liner.

7. A method as claimed in any preceding claim comprising alternately, repeatedly increasing and decreasing the pressure applied to said pulsation chamber (32,34) during said off portion of said pulsation cycle.

8. A method as claimed in any preceding claim further comprising alternately, repeatedly increasing and decreasing the pressure applied to said pulsation chamber during said on portion of said pulsation cycle.

9. A method as claimed in any preceding claim wherein a pulsation cycle is provided by applying a first pressure level to said pulsation chamber (32,34) to open said liner (24,26) below the teat during the on portion of said pulsation cycle, and applying a second pressure level, higher than said first pressure level, to said pulsation chamber to collapse and close said liner below the teat during the off portion of said pulsation cycle.

10. A method as claimed in claim 9 comprising a plurality of pulsation cycles which provide a milking interval, wherein the pressure change transition time from said second pressure level to said first pressure level during pulsation cycles at the end of said milking interval is lengthened to provide a decreasing-pressure transition time during pulsation cycles at the end of said milking interval which is longer than the decreasing-pressure transition time during pulsation cycles in the middle of said milking interval, to provide a slower rate of liner opening movement during pulsation cycles at the end of said milking interval than the rate of liner opening movement during pulsation cycles in the middle of said milking interval, to open said liner more slowly at the end of said milking interval than during the middle of said milking interval, for limiting loss of adhesion between a less than full teat and the interior of said liner at the end of said milking interval.

11. A method as claimed in claim 9 comprising a plurality of pulsation cycles which provide a milking interval wherein the pressure change transition time from said second pressure level to said first pressure level during pulsation cycles at the beginning of said milking interval is shortened to provide a decreasing-pressure transition time during pulsation cycles at the beginning of said milking interval which is shorter than the decreasing-pressure transition time during pulsation cycles in the middle of said milking interval, to provide a faster rate of liner opening movement during pulsation cycles at the beginning of said milking interval than the rate of liner opening movement during pulsation cycles in the middle of said milking interval, for opening said liner more rapidly at the beginning of said milking interval than during the middle of said milking interval so as to provide deeper teat penetration into the liner at the beginning of said milking interval.

12. A method as claimed in claim 9 comprising a plurality of pulsation cycles which provide a milking interval wherein the pressure change transition time from said second level to said first level is varied to provide a first decreasing-pressure transition time from said second level to said first level during pulsation cycles at the beginning of said milking interval, a second decreasing-pressure transition time from said second level to said first level during pulsation cycles in the middle of said milking interval, and a third decreasing-pressure transition time from said second level to said first level during pulsation cycles at the end of said milking interval, wherein said first transition time is less than said second transition time, and said third transition time is greater than said second transition time.

13. A method as claimed in any of claims 1 to 8 comprising a plurality of pulsation cycles which provide a milking interval wherein the pressure applied to said pulsation chamber during on portions of pulsation cycles at the end of said milking interval to open said liner is higher at the end of said milking interval than during the middle of said milking interval, for limiting loss of adhesion between a less than full teat and the interior of said liner at the end of said milking interval.

14. A method as claimed in any one of claims 1 to 8 comprising a plurality of pulsation cycles which provide a milking interval wherein the pressure applied to said pulsation chamber during on portions of pulsation cycles at the beginning of said milking interval to open said liner is lower at the beginning of said milking interval than during the middle of said milking interval, for providing deeper teat penetration into the liner at the beginning of said milking interval.

15. A method as claimed in any one of claims 1 to 8 comprising a plurality of pulsation cycles which provide a milking interval wherein the pressure applied to said pulsation chamber during on portions of pulsation cycles during said milking interval opens said liner to a first diameter at the beginning of said milking interval, and to a second diameter during the middle of said milking interval, and to a third diameter at the end of said milking interval, said first diameter being greater than said second diameter, and said second diameter being greater than said third diameter.

16. A method as claimed in any one of claims 1 to 15 comprising terminating said on portion of said pulsation cycle and initiating said off portion of said pulsation cycle in response to a decrease in milk flow rate.

17. A method according to any one of claims 1 to 12 comprising varying the pressure supplied to said pulsation chamber in response to a given parameter.

18. The method according to claim 17, wherein said given parameter is time.

19. The method according to claim 17, wherein said given parameter is milk flow rate.

20. Milking apparatus for milking a mammal, comprising:

a teat cup (12; 14) having a liner (24; 26) for location around a teat of a mammal;

a milk flow passage (28; 30) within said liner (24; 26), and a pulsation chamber (32; 34) located between said liner (24; 26) and said teat cup (12; 14);

a negative pressure source (48) for applying a negative pressure below atmospheric pressure to said milk flow passage (28; 30); and

a variable pressure source (82) for supplying a negative pressure to said pulsation chamber (32; 34) during an on portion of a pulsation cycle to open said liner (24; 26) below the teat and a higher pressure to said pulsation chamber (32; 34) during an off portion of said pulsation cycle to close said liner (24; 26) below the teat,

characterized in that the variable pressure source (82) is arranged to controllably vary the rate of pressure change applied to said pulsation chamber (32; 34) without a two-way valve pulsator, alternating between a first condition connecting a negative pressure source to the pulsation chamber and a second condition supplying atmospheric or higher pressure as on and off portions of a pulsation cycle;
wherein said variable pressure source (82) is arranged to supply a controllably variable pressure to said pulsation chamber (32; 34) and to vary the pressure supplied to said pulsation chamber (32; 34) along a controllably variable pressure curve of selectable waveshape, and
wherein said variable pressure source (82) is further arranged to provide an abrupt pressure change at the beginning of the transition from at least one of said on and off position of said pulsation cycle to the other of said on and off portions of said pulsation cycle, followed by a slower rate of pressure change.

21. The apparatus according to claim 20, wherein said variable pressure source is arranged to provide an abrupt pressure change at the end of said transition following said slower rate of pressure change, such that said variable pressure source provides a first abrupt pressure change followed by a slower rate of pressure change followed by a second abrupt pressure change, during said transition.

22. The apparatus according to any one of claims 20 to 21, wherein said variable pressure source is arranged to abruptly change the pressure applied to said pulsation chamber at a rate sufficiently fast that the transition time between said on and off portions of said pulsation cycle is limited primarily by the desired rate of movement of said liner between open and closed conditions.

23. The apparatus according to any one of claims 20 to 22, wherein variable pressure source is arranged to vary the pressure supplied to said pulsation chamber at a controllably variable repetition rate, to provide a plurality of pulsation cycles of variable duration.

24. The apparatus according to claim 23, wherein said variable pressure source is arranged to vary said waveshape from cycle to cycle.

25. The apparatus according to any one of claims 20 to 24, wherein said variable pressure source is arranged to supply pressure to said pulsation chamber in response to a given parameter.

26. The apparatus according to claim 25, wherein said given parameter is time.

27. The apparatus according to claim 25, wherein said given parameter is milk flow rate.

28. The apparatus according to any one of claims 20 to 27, wherein said variable pressure source comprises a pressure transducer.

Ansprüche

1. Verfahren zum Melken eines Säugetiers, wobei
ein Zitzenbecher (12; 14) mit einem um eine Zitze des Säugetiers herum anzuordnenden Einsatz (24; 26) vorgesehen wird,
in dem Einsatz (24; 26) ein Milchflußkanal (28; 30) und zwischen dem Einsatz (24; 26) und dem Zitzenbecher (12; 14) eine Pulsationskammer (32; 34) definiert wird,
auf den Milchflußkanal (28; 30) ein Unterdruck unter dem atmosphärischen Druck ausgeübt wird,
die Pulsationskammer während eines EIN-Teils eines Pulsationszyklus mit einem Unterdruck beaufschlagt wird, und
die Pulsationskammer während eines AUS-Teils des Pulsationszyklus mit einem höheren Druck beaufschlagt wird,
gekennzeichnet durch die Verwendung einer variablen Druckquelle (82) zur gesteuerten Änderung der Druckänderungsrate in der Pulsationskammer (32; 34),
ohne Verwendung eines Zweiwegeventil-Pulsators, der als EIN-Teil und AUS-Teil eines Pulsationszyklus alterniert zwischen einem ersten Zustand, in dem eine Unterdruckquelle mit der Pulsationskammer verbunden wird, und einem zweiten Zustand, in dem Atmosphärendruck oder ein höherer Druck zugeführt wird;
wobei die Pulsationskammer (32; 34) mit einem steuerbar veränderbaren Druck beaufschlagt wird und der die Pulsationskammer (32; 34) beaufschlagende Druck entlang einer steuerbar veränderbaren Druckkurve mit wählbarem Verlauf geändert wird,
wobei der Druck am Beginn des Übergangs von zumindest einem von EIN-Teil und AUS-Teil des Pulsationszyklus zu dem anderen von EIN-Teil und AUS-Teil des Pulsationszyklus abrupt geändert wird und dann mit geringerer Änderungsrate geändert wird, alles während des Übergangs.

2. Verfahren nach einem der vorhergehenden Ansprüche, wobei eine Unterdruckquelle (48) gemeinsam sowohl den an dem Milchflußkanal (28, 30) als auch den an der Pulsationskammer (32, 34) liegenden Unterdruck bereitstellt.

3. Verfahren nach einem der vorhergehenden Ansprüche, wobei der während des EIN-Teils des Pulsationszyklus an der Pulsationskammer liegende Druck steuerbar geändert wird.

4. Verfahren nach einem der vorhergehenden Ansprüche, wobei der Druck am Ende des Übergangs im Anschluß an die Änderung mit geringerer Rate abrupt geändert wird, so daß eine erste abrupte Druckänderung, sodann eine Druckänderung mit geringerer Rate, und anschließend eine zweite abrupte Druckänderung stattfindet, alles während des Übergangs.

5. Verfahren nach einem der vorhergehenden Ansprüche, wobei der an der Pulsationskammer liegende Druck mit einer Rate abrupt geändert wird, die ausreichend hoch ist, so daß die Übergangszeit zwischen den EIN- und AUS-Teilen des Pulsationszyklus nur durch die gewünschte Bewegungsgeschwindigkeit des Einsatzes zwischen dem offenen und dem geschlossenen Zustand begrenzt wird.

6. Verfahren nach Anspruch 5, wobei der an der Pulsationskammer liegende Druck mit einer Rate geändert wird, die die gewünschte maximale Bewegungsrate des Einsatzes erzeugt.

7. Verfahren nach einem der vorhergehenden Ansprüche, wobei der an der Pulsationskammer (32, 34) liegende Druck während des AUS-Teils des Pulsationszyklus wiederholt abwechselnd erhöht und verringert wird.

8. Verfahren nach einem der vorhergehenden Ansprüche, wobei der an der Pulsationskammer liegende Druck während des EIN-Teils des Pulsationszyklus wiederholt abwechselnd erhöht und verringert wird.

9. Verfahren nach einem der vorhergehenden Ansprüche, wobei ein Pulsationszyklus bereitgestellt wird, indem während des EIN-Teils des Pulsationszyklus ein erster Druckpegel an die Pulsationskammer (32, 34) angelegt wird, um den Einsatz (24, 26) unterhalb der Zitze zu öffnen, und während des AUS-Teils des Pulsationszyklus an die Pulsationskammer ein über dem ersten Druckpegel gelegener zweiter Druckpegel angelegt wird, um den Einsatz unterhalb der Zitze zu kollabieren und zu schließen.

10. Verfahren nach Anspruch 9 mit mehreren ein Melkintervall bildenden Pulsationszyklen, wobei die Übergangszeit der Druckänderung vom zweiten zum ersten Druckpegel während Pulsationszyklen am Ende des Melkintervalls verlängert wird, um während Pulsationszyklen am Ende des Melkintervalls eine Übergangszeit mit verringertem Druck vorzusehen, die länger ist als die Übergangszeit mit verringertem Druck während Pulsationszyklen in der Mitte des Melkintervalls, und um während Pulsationszyklen am Ende des Melkintervalls eine geringere Geschwindigkeit in der Öffnungsbewegung des Einsatzes vorzusehen als während Pulsationszyklen in der Mitte des Melkintervalls, um den Einsatz am Ende des Melkintervalls langsamer zu öffnen als während der Mitte des Melkintervalls und dadurch den Verlust an Haftung zwischen einer nicht mehr vollen Zitze und dem Inneren des Einsatzes am Ende des Melkintervalls zu begrenzen.

11. Verfahren nach Anspruch 9 mit mehreren ein Melkintervall bildenden Pulsationszyklen, wobei die Übergangszeit der Druckänderung vom zweiten zum ersten Druckpegel während Pulsationszyklen am Beginn des Melkintervalls verkürzt wird, um während Pulsationszyklen am Beginn des Melkintervalls eine Übergangszeit mit abnehmendem Druck vorzusehen, die kürzer ist als die Übergangszeit mit abnehmendem Druck während Pulsationszyklen in der Mitte des Melkintervalls, um so während Pulsationszyklen am Beginn des Melkintervalls eine höhere Rate der Öffnungsbewegung des Einsatzes zu erreichen als während Pulsationszyklen in der Mitte des Melkintervalls und somit den Einsatz am Beginn des Melkintervalls rascher zu öffnen als während der Mitte des Melkintervalls, so daß die Zitze am Beginn des Melkintervalls tiefer in den Einsatz eintaucht.

12. Verfahren nach Anspruch 9 mit mehreren ein Melkintervall bildenden Pulsationszyklen, wobei die Übergangszeit der Druckänderung vom zweiten zum ersten Pegel geändert wird, um während Pulsationszyklen am Beginn des Melkintervalls eine erste Übergangszeit mit abnehmendem Druck vom zweiten zum ersten Pegel, während Pulsationszyklen in der Mitte des Melkintervalls eine zweite Übergangszeit mit abnehmendem Druck vom zweiten zum ersten Pegel und während Pulsationszyklen am Ende des Melkintervalls eine dritte Übergangszeit mit abnehmendem Druck vom zweiten zum ersten Pegel vorzusehen, wobei die erste Übergangszeit kürzer ist als die zweite Übergangszeit und die dritte Übergangszeit länger ist als die zweite Übergangszeit.

13. Verfahren nach einem der Ansprüche 1 bis 8 mit mehreren ein Melkintervall bildenden Pulsationszyklen, wobei der während EIN-Teilen von Pulsationszyklen am Ende des Melkintervalls an der Pulsationskammer liegende Druck zum Öffnen des Einsatzes am Ende des Melkintervalls größer ist als während der Mitte des Melkintervalls, um Verluste in der Haftung zwischen einer nicht mehr vollen Zitze und dem Inneren des Einsatzes am Ende des Melkintervalls zu begrenzen.

14. Verfahren nach einem der Ansprüche 1 bis 8 mit mehreren ein Melkintervall bildenden Pulsationszyklen, wobei der während EIN-Teilen von Pulsationszyklen am Beginn des Melkintervalls an der Pulsationskammer liegende Druck zum Öffnen des Einsatzes am Beginn des Melkintervalls geringer ist als während der Mitte des Melkintervalls, so daß die Zitze am Beginn des Melkintervalls tiefer in den Einsatz eintaucht.

15. Verfahren nach einem der Ansprüche 1 bis 8 mit mehreren ein Melkintervall bildenden Pulsationszyklen, wobei der während EIN-Teilen von Pulsationszyklen während des Melkintervalls an der Pulsationskammer liegende Druck den Einsatz am Beginn des Melkintervalls auf einen ersten Durchmesser, während der Mitte des Melkintervalls auf einen zweiten Durchmesser und am Ende des Melkintervalls auf einen dritten Durchmesser öffnet,
wobei der erste Durchmesser größer ist als der zweite Durchmesser und der zweite Durchmesser größer ist als der dritte Durchmesser.

16. Verfahren nach einem der Ansprüche 1 bis 15, wobei bei Abnahme der Milchflußrate der EIN-Teil des Pulsationszyklus beendet und der AUS-Teil des Pulsationszyklus eingeleitet wird.

17. Verfahren nach einem der Ansprüche 1 bis 12, wobei der an der Pulsationskammer liegende Druck nach einem vorgegebenen Parameter geändert wird.

18. Verfahren nach Anspruch 17, wobei der vorgegebene Parameter die Zeit ist.

19. Verfahren nach Anspruch 17, wobei der vorgegebene Parameter die Milchflußrate ist.

20. Melkapparat zum Melken eines Säugetiers, umfassend
einen Zitzenbecher (12; 14) mit einem um eine Zitze des Säugetiers herum anzuordnenden Einsatz (24; 26),
einen Milchflußkanal (28; 30) in dem Einsatz (24; 26) und eine Pulsationskammer (32; 34) zwischen dem Einsatz (24; 26) und dem Zitzenbecher (12; 14),
eine Unterdruckquelle (48) zum Anlegen eines Unterdrucks unterhalb des atmosphärischen Drucks an den Milchflußkanal (28; 30), und
eine variable Druckquelle (82) zum Anlegen eines Unterdrucks an die Pulsationskammer (32; 34) während eines EIN-Teils eines Pulsationszyklus, um den Einsatz (24; 26) unter der Zitze zu öffnen, und eines höheren Drucks während eines AUS-Teils des Pulsationszyklus, um den Einsatz (24; 26) unter der Zitze zu schließen,
dadurch gekennzeichnet,
daß die variable Druckquelle (82) ausgelegt ist zur gesteuerten Änderung der Änderungsrate des an der Pulsationskammer liegenden Drucks,
ohne Verwendung eines Zweiwegeventil-Pulsators, der als EIN-Teil und AUS-Teil eines Pulsationszyklus alterniert zwischen einem ersten Zustand, in dem eine Unterdruckquelle mit der Pulsationskammer verbunden wird, und einem zweiten Zustand, in dem Atmosphärendruck oder ein höherer Druck zugeführt wird,
wobei die variable Druckquelle (82) auf die Zuführung eines gesteuerten variablen Drucks zu der Pulsationskammer (32, 34) und die Änderung des an der Pulsationskammer (32; 34) liegenden Drucks entlang einer steuerbar veränderbaren Druckkurve mit wählbarem Verlauf ausgelegt ist, und
wobei die variable Druckquelle (82) weiter auf die Erzeugung einer abrupten Druckänderung am Beginn des Übergangs von zumindest einem der EIN- und AUS-Teile des Pulsationszyklus zu dem anderen der EIN- und AUS-Teile des Pulsationszyklus und anschließend einer Druckänderung mit geringerer Änderungsrate ausgelegt ist.

21. Apparat nach Anspruch 20, wobei die variable Druckquelle auf die Erzeugung einer abrupten Druckänderung am Ende des Übergangs im Anschluß an die Änderung mit geringerer Rate ausgelegt ist, so daß sie während des Übergangs eine erste abrupte Druckänderung, sodann eine Druckänderung mit geringerer Rate und anschließend eine zweite abrupte Druckänderung erzeugt.

22. Apparat nach einem der Ansprüche 20 bis 21, wobei die variable Druckquelle auf die abrupte Änderung des an der Pulsationskammer liegenden Drucks mit einer Rate ausgelegt ist, die ausreichend hoch ist, daß die Übergangszeit zwischen den EIN- und AUS-Teilen des Pulsationszyklus primär durch die gewünschte Bewegungsgeschwindigkeit des Einsatzes zwischen dem offenen und dem geschlossenen Zustand begrenzt wird.

23. Apparat nach einem der Ansprüche 20 bis 22, wobei die variable Druckquelle auf die Änderung des an der Pulsationskammer liegenden Drucks mit steuerbar veränderbarer Wiederholrate steuerbar ausgelegt ist, um mehrere Pulsationszyklen variabler Dauer zu erzeugen.

24. Apparat nach Anspruch 23, wobei die variable Druckquelle auf die Änderung des Kurvenverlaufs von Zyklus zu Zyklus ausgelegt ist.

25. Apparat nach einem der Ansprüche 20 bis 24, wobei die variable Druckquelle auf die Änderung des an der Pulsationskammer liegenden Drucks nach einem vorgegebenen Parameter ausgelegt ist.

26. Apparat nach Anspruch 25, wobei der vorgegebene Parameter die Zeit ist.

27. Apparat nach Anspruch 25, wobei der vorgegebene Parameter die Milchflußrate ist.

28. Apparat nach einem der Ansprüche 20 bis 27, wobei die variable Druckquelle einen Druckwandler aufweist.

Revendications

1. Procédé de traite d'un mammifère, comprenant les étapes qui consistent à
prévoir un gobelet trayeur (12, 14) comportant un manchon (24, 26) destiné à être positionné autour d'un trayon du mammifère
définir un passage d'écoulement de lait à l'intérieur dudit manchon et une chambre de pulsation (32, 34) entre ledit manchon et ledit gobelet trayeur (12, 14)
appliquer une pression négative inférieure à la pression atmosphérique audit passage (28, 30) d'écoulement de lait ;
fournir une pression négative à ladite chambre de pulsation(32, 34) au cours d'une partie de travail d'un cycle de pulsation ;
fournir une pression plus élevée à ladite chambre de pulsation au cours d'une partie de repos dudit cycle de pulsation ;
caractérisé par l'emploi d'une source de pression (82) variable pour faire varier de manière contrôlable la vitesse de changement de pression dans ladite chambre de pulsation (32, 34) sans utilisation d'un pulsateur à soupape à deux voies alternant entre une premier état de connexion d' une source de pression négative à la chambre de pulsation et un deuxième état fournissant une pression atmosphérique ou supérieure en tant que partie de travail ou de repos d'un cycle de pulsation;
la méthode comprenant la fourniture d'une pression variable de manière contrôlée à ladite chambre de pulsation (32, 24) et la variation de la pression fournie à ladite chambre de pulsation (32,34) suivant une courbe de pression variable de manière contrôlable ayant une forme d'onde sélectionnable, la méthode comportant de plus le changement brusque de la pression au début de ladite transition entre l'une au moins desdites parties de travail et de repos dudit cycle de pulsation et l'autre desdites parties de travail et de repos dudit cycle de pulsation, puis la variation de la pression à une vitesse plus lente, le tout pendant ladite transition.

2. Procédé tel que défini dans l'une quelconque des revendications précédentes, selon lequel une source de pression négative (48) fournit conjointement ladite pression négative appliquée audit passage d'écoulement de lait (28, 30) et ladite pression négative appliquée à ladite chambre de pulsation (32, 34).

3. Procédé tel que défini dans l'une quelconque des revendications précédentes, comprenant la variation contrôlable de la pression appliquée à ladite chambre de pulsation au cours de ladite partie de travail dudit cycle de pulsation.

4. Procédé selon n'importe laquelle des revendications précédentes, comprenant le changement brusque de la pression à la fin de ladite transition suivant ledit changement de pression à une vitesse plus lente, de façon à créer un premier changement de pression brusque, suivi d'un changement de pression à une vitesse plus lente, suivi d'un second changement de pression brusque, le tout pendant ladite transition.

5. Procédé tel que défini dans l'une quelconque des revendications précédentes, comprenant le changement brusque de la pression appliquée à ladite chambre de pulsation à une vitesse suffisamment rapide pour que la période de transition entre lesdites parties de travail et de repos dudit cycle de pulsation soit limitée uniquement par la vitesse de mouvement souhaitée dudit manchon entre des états ouvert et fermé.

6. Procédé tel que défini dans la revendication 5, comprenant le changement de la pression appliquée à ladite chambre de pulsation à une vitesse engendrant la vitesse de mouvement maximale souhaitée dudit manchon.

7. Procédé tel que défini dans l'une quelconque des revendications précédentes, comprenant l'augmentation et la diminution alternées et répétées de la pression appliquée à ladite chambre de pulsation (32, 34) au cours de ladite partie de repos dudit cycle de pulsation.

8. Procédé tel que défini dans l'une quelconque des revendications précédentes, comprenant également l'augmentation et la diminution alternées et répétées de la pression appliquée à ladite chambre de pulsation au cours de ladite partie de travail dudit cycle de pulsation.

9. Procédé tel que défini dans l'une quelconque des revendications précédentes, selon lequel un cycle de pulsation est établi par l'application à ladite chambre de pulsation (32, 34) d'un premier niveau de pression pour ouvrir ledit manchon (24, 26) au-dessous du trayon au cours de la partie de travail dudit cycle de pulsation, et d'un second niveau de pression, supérieur audit premier niveau de pression, pour écraser et fermer ledit manchon au dessous du trayon au cours de la partie de repos dudit cycle de pulsation.

10. Procédé tel que défini dans la revendication 9, comprenant plusieurs cycles de pulsation qui définissent un intervalle de traite, selon lequel la période de transition de changement de pression entre ledit second niveau de pression et ledit premier niveau de pression au cours de cycles de pulsation qui ont lieu à la fin dudit intervalle de traite est rallongée pour définir pendant ceux-ci une période de transition à pression décroissante, plus longue que la période de transition à pression décroissante au cours de cycles de pulsation qui ont lieu au milieu dudit intervalle de traite, afin de permettre au cours des cycles de pulsation qui ont lieu à la fin dudit intervalle de traite une vitesse de mouvement d'ouverture du manchon plus lente qu'au cours des cycles de pulsation qui ont lieu au milieu dudit intervalle de traite, pour ouvrir ledit manchon plus lentement à la fin dudit intervalle de traite qu'au milieu de celui-ci, en vue de limiter une perte d'adhérence entre un trayon moins que plein et l'intérieur dudit manchon à la fin dudit intervalle de traite.

11. Procédé tel que défini dans la revendication 9, comprenant plusieurs cycles de pulsation qui définissent un intervalle de traite, selon lequel la période de transition de changement de pression entre ledit second niveau de pression et ledit premier niveau de pression au cours de cycles de pulsation qui ont lieu au début dudit intervalle de traite est raccourcie pour définir pendant ceux-ci une période de transition à pression décroissante, plus courte que la période de transition à pression décroissante au cours de cycles de pulsation qui ont lieu au milieu dudit intervalle de traite, afin de permettre au cours des cycles de pulsation qui ont lieu au début dudit intervalle de traite une vitesse de mouvement d'ouverture du manchon plus rapide qu'au cours des cycles de pulsation qui ont lieu au milieu dudit intervalle de traite, pour ouvrir ledit manchon plus rapidement au début dudit intervalle de traite qu'au milieu de celui-ci, de façon à permettre une pénétration plus profonde du trayon dans le manchon au début dudit intervalle de traite.

12. Procédé tel que défini dans la revendication 9, comprenant plusieurs cycles de pulsation qui définissent un intervalle de traite, selon lequel la période de transition de changement de pression entre ledit second niveau et ledit premier niveau varie pour définir une première période de transition à pression décroissante entre ledit second niveau et ledit premier niveau au cours de cycles de pulsation qui ont lieu au début dudit intervalle de traite, une deuxième période de transition à pression décroissante entre ledit second niveau et ledit premier niveau au cours de cycles de pulsation qui ont lieu au milieu dudit intervalle de traite, et une troisième période de transition à pression décroissante entre ledit second niveau et ledit premier niveau au cours de cycles de pulsation qui ont lieu à la fin dudit intervalle de traite, ladite première période de transition étant inférieure à ladite deuxième période de transition, et ladite troisième période de transition étant supérieure à ladite deuxième période de transition.

13. Procédé tel que défini dans l'une quelconque des revendications 1 à 8, comprenant plusieurs cycles de pulsation qui définissent un intervalle de traite, selon lequel la pression appliquée à ladite chambre de pulsation au cours de parties de travail de cycles de pulsation qui ont lieu à la fin dudit intervalle de traite pour ouvrir ledit manchon est plus faible à la fin dudit intervalle de traite qu'au milieu de celui-ci, en vue de limiter une perte d'adhérence entre un trayon moins que plein et l'intérieur dudit manchon à la fin dudit intervalle de traite.

14. Procédé tel que défini dans l'une quelconque des revendications 1 à 8, comprenant plusieurs cycles de pulsation qui définissent un intervalle de traite, selon lequel la pression appliquée à ladite chambre de pulsation au cours de parties de travail de cycles de pulsation qui ont lieu au début dudit intervalle de traite pour ouvrir ledit manchon est plus élevée au début dudit intervalle de traite qu'au milieu de calui-ci, en vue de permettre une pénétration plus profonde du trayon dans le manchon au début dudit intervalle de traite.

15. Procédé tel que défini dans l'une quelconque des revendications 1 à 8, comprenant plusieurs cycles de pulsation qui définissent un intervalle de traite selon lequel la pression appliquée à ladite chambre de pulsation au cours de parties de travail de cycles de pulsation pendant ledit intervalle de traite ouvre ledit manchon à un premier diamètre au début dudit intervalle de traite, à un deuxième diamètre au milieu dudit intervalle de traite, et à un troisième diamètre à la fin dudit intervalle de traite, ledit premier diamètre étant supérieur audit deuxième diamètre, et ledit deuxième diamètre étant supérieur audit troisième diamètre.

16. Procédé tel que défini dans l'une quelconque des revendications 1 à 15, comprenant la terminaison de ladite partie de travail dudit cycle de pulsation et le commencement de ladite partie de repos dudit cycle de pulsation en réponse à une diminution d'un débit de lait.

17. Procédé selon l'une quelconque des revendications 1 à 12, comprenant la variation de la pression fournie à ladite chambre de pulsation en réponse à un paramètre donné.

18. Procédé selon la revendication 17, suivant lequel ledit paramètre donné est un temps.

19. Procédé selon la revendication 17, suivant lequel ledit paramètre donné est un débit de lait.

20. Appareil de traite pour traire un mammifère, comprenant
un gobelet trayeur (12, 14) comportant un manchon (24, 26) destiné à être positionné autour d'un trayon du mammifère;
un passage d'écoulement de lait (28,30) prévu à l'intérieur dudit manchon (24, 26), et une chambre de pulsation (32, 34) située entre ledit manchon (24,26) et ledit gobelet trayeur (12, 14);
une source de pression négative (48) destinée à appliquer audit passage (28, 30) d'écoulement de lait une pression négative inférieure à la pression atmosphérique; et
une source de pression variable (82) destinée à fournir à ladite chambre de pulsation (32,34) une pression négative au cours d'une partie de travail d'un cycle de pulsation afin d'ouvrir ledit manchon (24, 26) au-dessous du trayon, et une pression plus élevée à ladite chambre de pulsation (32, 34) au cours d'une partie de repos dudit cycle de pulsation afin de fermer ledit manchon (24, 26) au-dessous du trayon,
caractérisé en ce que la source de pression variable (82) est conçue pour faire varier de manière contrôlable la vitesse de changement de pression appliquée à ladite chambre de pulsation (32, 34) sans un pulsateur à soupape à deux voies, alternant entre un premier état de connexion d' une source de pression négative à la chambre de pulsation et un deuxième état fournissant une pression atmosphérique ou supérieure en tant que partie de travail ou de repos d'un cycle de pulsation;
dans lequel ladite source de pression variable (82) est conçue pour fournir une pression variable de manière contrôlable à ladite chambre de pulsation (32, 34) et pour faire varier la pression fournie à ladite chambre de pulsation (32, 34) suivant une courbe de pression variable de manière contrôlable ayant une forme d'onde sélectionnable, et
dans lequel ladite source de pression variable (82) est de plus conçue pour créer un changement de pression brusque au début de ladite transition entre l'une au moins desdites parties de travail et de repos dudit cycle de pulsation et l'autre desdites parties de travail et de repos dudit cycle de pulsation, suivi d'un changement de pression à une vitesse plus lente.

21. Appareil selon la revendication 20 dans lequel le changement brusque de la pression à la fin de ladite transition suivant ledit changement de pression à une vitesse plus lente, de façon à créer un premier changement de pression brusque, suivi d'un changement de pression à une vitesse plus lente, suivi d'un second changement de pression brusque, le tout pendant ladite transition.

22. Appareil selon l'une quelconque des revendications 20 à 21, dans lequel ladite source de pression variable est conçue pour changer brusquement la pression appliquée à ladite chambre de pulsation à une vitesse suffisamment rapide pour que la période de transition entre lesdites parties de travail et de repos dudit cycle de pulsation soit limitée principalement par la vitesse de mouvement souhaitée dudit manchon entre des états ouvert et fermé.

23. Appareil selon l'une quelconque des revendications 20 à 22, dans lequel ladite source de pression variable est conçue pour faire varier la pression fournie à ladite chambre de pulsation à une vitesse de répétition variable de manière contrôlable afin de définir plusieurs cycles de pulsation de durée variable.

24. Appareil selon la revendication 23, dans lequel ladite source de pression variable est conçue pour faire varier ladite forme d'onde d'un cycle à l'autre.

25. Appareil selon l'une quelconque des revendications 20 à 24, dans lequel ladite source de pression variable est conçue pour fournir une pression à ladite chambre de pulsation en réponse à un paramètre donné.

26. Appareil selon la revendication 25, dans lequel ledit paramètre donné est un temps.

27. Appareil selon la revendication 25, dans lequel ledit paramètre donné est un débit de lait.

28. Appareil selon l'une quelconque des revendications 20 à 27, dans lequel ladite source de pression variable comprend un transducteur de pression.

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